Loss or deregulation of proteins involved in such diverse processes as cellular proliferation, cell cycle control, DNA repair, cell death and checkpoint control is a consistent feature of cancer cells. Cancer cells arise through a process of cellular evolution due to the accumulation of genetic changes. As cancers arise and progress there is a selection for those genetic changes that give the cancer cell a proliferative advantage over normal cells. Because many cancers are not early detected at early stages of development nor readily curable using existing strategies, there is a need to identify new molecules that can be used both as diagnostic programs and as therapeutic targets. The Cellular Proliferation Program is organized around the theme that elucidating the web of connections between signal transduction pathways, cell cycle regulatory pathways and checkpoint pathways will help both to define origins of human cancer and to identify targets for the design of novel therapies and diagnostic tools. The Cellular Proliferation Program includes 22 members representing six academic departments. Research activities of members of this Program focus on fundamental biological processes regulating cellular proliferation, including signal transduction, cell cycle regulation and checkpoint control. These laboratories employ a diverse array of experimental approaches and model organisms including budding yeast, fission yeast, Caenorhabditis, elegans, Xenopus and mammalian systems. Investigators in the Program have a strong record of collaboration and interaction with other Siteman Cancer Center members. A major goal of the Program is to promote collaboration and translation of new findings regarding basic biological processes into opportunities for understanding oncogenesis.